And it didn't take hours of working out at the gym every day to get that benefit.

"The results of this study send a very practical message, which is that even a very realistic, moderate amount of exercise -- which we define as brisk walking for 150 minutes per week -- can provide a huge health benefit, particularly to people predisposed to hypertension because of their family history," researcher Robin P. Shook, a doctoral graduate student in the Arnold School of Public Health at the University of South Carolina in Columbia, says in a news release.

Having a parent with high blood pressure is one of the biggest risk factors for developing the condition yourself. Previous research suggests that having a parent with high blood pressure may account for about 35% to 65% of the variability of blood pressure levels.

The Physical Fitness Factor

The new study, published in Hypertension, included more than 6,000 healthy adults. About a third of them had a parent with high blood pressure.

Their physical fitness levels were followed for nearly five years.

The results confirmed that people who had a parent with high blood pressure were more likely to develop high blood pressure -- about 20% more likely, after considering other risk factors, including age, smoking, high cholesterol, and being overweight.

But the researchers found some good news for people with and without a family history of the disease, and physical fitness was the key.

People with a high level of physical fitness were 42% less likely to have high blood pressure and those with a moderate level of fitness were 26% less likely, compared to people with a low level of physical fitness.

Among people with a parent with high blood pressure, those who were most physically fit had only a 16% higher risk of developing high blood pressure than those who were fit and had no family history of the disease.